1. Field of the Invention
The present invention relates to a battery having an anode active material layer containing silicon (Si) as an element.
2. Description of the Related Art
In recent years, as mobile devices have been sophisticated and multi-functionalized, a higher capacity of secondary batteries as a power source for the mobile devices has been demanded. As a secondary battery to meet such a demand, there are a lithium ion secondary batteries. In the lithium ion secondary batteries currently in practical use, graphite is used for the anode. Therefore, the battery capacity thereof is in a saturated state, and attaining a greatly high capacity thereof is difficult. Therefore, it has been considered to use silicon or the like for the anode. In these years, forming an anode active material layer on an anode current collector by vapor-phase deposition method or the like has been reported (for example, refer to Japanese Unexamined Patent Application Publication Nos. H08-50922 and H11-135115, and Japanese Patent Publication No. 2948205). Since silicon or the like is largely expanded and shrunk due to charge and discharge, lowering of the cycle characteristics due to pulverization of silicon has been a disadvantage. However, by using vapor-phase deposition method or the like, pulverization can be prevented, and the anode current collector and the anode active material layer can be integrated. Therefore, electron conductivity in the anode becomes greatly favorable, and attaining high performance both in the capacity and the cycle life is expected.